Linux graphic 架構還滿複雜的, 在看時需要大略了解几個名詞及之間的關係. X Window System: 目前來到第11版本所以叫X11, 是以X window System Core protocol為基礎的window system. wayland: 由於X11太過複雜且在embbeded system中的效能不佳, 用來取代X window System Core protocol. weston (wayland compositor): 以wayland protocol來實做的compositor做為參考的範例, 實用上會用Westeros, Clutter…等. KMS/UMS: Kernel mode-setting 及User mode-setting. OpenGL: 由Khronos Group制定的跨平台graphic API. GLX: 是一個extension, 做為OpenGL與X window system之間的橋樑. 就像embedded system的EGL, MacOS的AGL. DRM(Direct Rendering Manager): 為了防止世界被破壞, 保護世界的和平. 防止同時使用graphic buffer. DRI(Direct Rendering Infrastructure): Mesa及DRM之間的橋樑. Ref: Introduction to the Direct Rendering Infrastructure CRTC (CRT Controller): Crtc is in charge of reading the framebuffer memory and routes the data to an encoder. ...

How to enable and test gzip in Nginx. Official document: ngx_http_gzip_module Enable gzip I use Raspberry Pi System Monitor to test gzip module. Modify /etc/nginx/sites-available/default to enable gzip. In this case I only change the RpiMonitor website in the server, you can apply it to global by /etc/nginx/nginx.conf location /rpi { proxy_pass http://127.0.0.1:9999/RpiMonitor; } Change to location /rpi { proxy_pass http://127.0.0.1:9999/RpiMonitor; gzip on; gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript; gzip_proxied any; } Then reload nginx.conf via sudo nginx -s reload ...

以前球隊在回防時, 教練總會說"快跑! 別回頭, 到定點再休息". 關於人生, 喘息點在哪兒? 我想就在滴水穿石之間! 失速的這個月 Week14 (04/07) 網路文章 Adding A New System Service To Android 5: Tips and How To 由下到上打造一個android system service. HW -> HAL -> JNI -> Service -> Manager -> Registering. Adding New System Service in Android Native system service. 33 Foods that Starve Cancer 滿有趣的論點, 細胞沒有supplement會死亡沒錯, 但microscopic cancers能否自己生出新的血管? 大部份的癌症無關基因, 超過40歲體內難免會有microscopic cells, 並可能轉變成cancer cells? Week15 (04/14) img2ascii.py 參考網路上的做法, 加了些參數方便調整輸出的內容. pillow提供便利的API. 網路文章 Every attempt to manage academia makes it worse Goodhart’s Law： “When a measure becomes a target, it ceases to be a good measure.” 為了打分數而訂出的評分系統, 不就是考試?! 衡量對錯本來就很難（也許本身就是個假議題）, 就像"找到一個對的人做對的事". The Cobra Effect： 在大公司應該是無可避免的. 網路資源 Python libhunt 可用找lib, 比較lib之間的活躍程度, Code Quality L1是較差, L5較佳. 除了python之外, 還有C++, Android, Java, Javascript…等. 讀書心得 The Handstand Builder For Women - Week1 Recap Week1, 有些人說Handstand不太需要flexibility, 我的經驗是stretches也是很重要的, 靈活的關節/彈性的肌肉能避免運動傷害. Reverse Plank: 有助於倒立時開胸姿態 Handstand against the wall: 讓身體習慣倒立姿態 Crescent Lunge/Seated Hamstring Stretch: 腿離地時腳筋的柔軟度很重要, 柔軟度不夠需要更大的肌力做平衡. Week16 (04/21) 網路文章 What is the difference between venv, pyvenv, pyenv, virtualenv, virtualenvwrapper, pipenv, etc? 一般是用virtualenv測試module需要哪些python packages, pyenv來測試module在不同的python2.6, python2.7, python3.5, python3.6是否正常. virtualenvwrapper是加強virtualenv的plugin, 將不同的環境放在同一個目錄方便管理. ...

Study USB MTP Device and Host mode in Android M. Source Code Cross Reference: Android 6.0.1_r10 MTP Device Mode Enable device mode: Settings -> Developer options -> Select USB Configuration -> MTP UsbDeviceManager: Setting USB config to mtp device/lge/hammerhead/init.hammerhead.usb.rc : on property:sys.usb.config=mtp system/core/rootdir/init.usb.configfs.rc: on property:sys.usb.config=mtp && property:sys.usb.configfs=1 USB plug to PC: MtpReceiver: listen to android.hardware.usb.action.USB_STATE and bring up MtpService UsbDeviceManager: get uevent USB_STATE=CONFIGURED from kernel MtpService: create MtpDatabase MtpDatabase: create volume and storage path MtpService: starting MTP server in MTP mode ...

以前球隊在回防時, 教練總會說"快跑! 別回頭, 到定點再休息". 關於人生, 喘息點在哪兒? 我想就在滴水穿石之間! Week9 (03/03) 228的4天連假讓這週過的特別快. 網路文章 What Americans can learn from other food cultures Google breaks SHA-1 web crypto for good but Torvalds plays down impact on Git Announcing the first SHA1 collision Google 公怖與CWI Amsterdam合作生出了第一個SHA-1 collision, 對於使用SHA-1的Git來說會有什麼影響? 目前看來是影響不大, 主因如下: Git remote 與 local 發生衝突時local並不會被override. 相較於Git, PDF檔是較容易被破解的. Git可能會計劃使用SHA3-256為新的hash algorithm. 為什麼不選SHA256? “SHA256 acceleration is mainly an ARM thing” - Torvalds 網路資源 Math is Fun: Common Core Standards: 基本數學. 讀書心得 Learning How to Learn - Week1 這週以科學研究來看大腦對於學習的反應 可以把學習看的很單純, 就是"不斷"的吸收及練習, “不斷"意指長遠的時間1年, 5年, 10年…等, 而不是指當下不斷的行為. 很多名人傳記都有提及他們的看書習慣, Ex: Steven Jobs and Elon Musk. Think mode: focus, and diffuse. After leaning and sleeping brain form many synapses on the dendrite in your brain that is how your brain upgrade after a sleep or nap. Procrastination - The Pomodoro Technique: an intense 25 minutes followed by 5 minutes relaxation or a little reward. Memory - long term memory and working memory are two major memory systems. Research has shown that if you try to glue things into your memory by repeating something twenty times in one evening, for example, it won’t stick nearly as well as if you practice it the same number of times over several days. Sleep - When you sleep, your brain cells shrink, which allows toxins to be more easily washed away. Week10 (03/10) 網路文章 I Was Wrong About Speed Reading: Here are the Facts Reading包含几種不同的方法: saccade, scan, and skim. 以前只知道scan and skim, 但saccadé是法文, 意思跟scan似乎是一樣的. 在reading時有几個過程: fixate, saccade and process. Subvocalization是必要的, 用來幫助理解(process). 從解剖學及神經學來看, 速讀是有極限的. 英文極限約500wpm, 超過這個速度還能讀懂文章, 我想對於文章內容很熟的成份居多. 文中提到的tips其實就是six-way paragraphs的方法. ...

Vi用慣了, 那在shell也可以vi-style嗎? 答案是可以的! 這個方法可使用在常用的shell, 例如bash, ksh, zsh, mksh. btw, mksh 是Android使用的shell, 但Ubuntu預設的dash 是不支援的. 在shell中執行set -o vi 後按’i’進入insert mode, ‘ESC’為normal mode. 回到原本的模式則是set -o emacs 如下圖: Reference: Using vi-mode in your shell

CWI Institute in Amsterdam and Google genrate two PDF documents with the same SHA-1 digest. Google security blog - Announcing the first SHA1 collision SHA-1 collistion and Git If a file A with X hash in local repository and with X hash in remote (SHA-1 collistion between local and remote), would overwrite the local version? Nope. If it has the same SHA1, it means that when we receive the object from the other end, we will not overwrite the object we already have. So you have two cases of collision: the inadvertent kind, … The attacker kind … … So in this case, the collision is entirely a non-issue: you’ll get a “bad” repository that is different from what the attacker intended, but since you’ll never actually use his colliding object, it’s literally no different from the attacker just not having found a collision at all, but just using the object you already had (ie it’s 100% equivalent to the “trivial” collision of the identical file generating the same SHA1). See above. The only dangerous kind of collision is the inadvertent kind, but that’s obviously also the very very unlikely kind. Torvalds @ Git- Re: Starting to think about sha-256? ...